This invention relates to a vapor-cooled transformer and, more particularly, to a bubble deflector for such vapor-cooled transformer.
As is well known to those skilled in the transformer art it is necessary that the dielectric strength of the cooling and insulating liquid be maintained throughout the life of the transformer. In oil-cooled apparatus the oil and other insulation are thoroughly dried to prevent water accumulation. Further, the equipment is usually filled under vacuum to prevent any air from forming in the system. Since air has a dielectric constant of approximately one, which is substantially lower than that of oil, any air in the system will assume a disproportionate share of the dielectric stress which could, of course, lead to a possible failure of the transformer.
In vapor-cooled transformers the cooling is provided by the boiling or vaporization of the liquid in the transformer. The operation of vapor-cooled transformers is more fully disclosed in application Ser. No. 843,676 filed Oct. 19, 1977 for "Percolation Cooled Transformer" in the name of R. E. Gearhart et al (the applicant herein) and which is assigned to the same assignee as this application. As will be understood, the vapor bubbles also have a low dielectric constant of one as compared to the dielectric constant of 2.2 or more for the cooling and insulating fluid of the vapor-cooled transformer. If these vapor bubbles should accumulate between the coil, which is at a high voltage, and the core, which is normally at ground, a failure could occur between these components across such vapor bubble.
It is one object of this invention to provide a bubble deflector between the core and coil of a vapor-cooled transformer to prevent the accumulation of vapor bubbles between such core and coil.
A further object of this invention is to provide a bubble deflector beneath the lower portion of the upper yoke of the core and above the coil of a vapor-cooled transformer.